Insights into radiation damage from atomic resolution scanning transmission electron microscopy imaging of mono-layer CuPcCl$_{16}$ films on graphene

TL;DR

This study uses low-dose transmission electron microscopy to observe radiation damage mechanisms in monolayer CuPcCl₁₆ crystals on graphene, providing insights into their stability and enabling characterization of 2D organic-inorganic composites.

Contribution

It presents the first atomically resolved imaging of monolayer organic crystals under electron beam and elucidates their radiation damage processes.

Findings

Identified radiation damage mechanisms in 2D organic crystals.

Achieved undamaged molecular imaging with low-dose electron microscopy.

Enabled characterization of 2D organic-inorganic composites.

Abstract

Atomically resolved images of monolayer organic crystals have only been obtained with scanning probe methods so far. On the one hand, they are usually prepared on surfaces of bulk materials, which are not accessible by (scanning) transmission electron microscopy. On the other hand, the critical electron dose of a monolayer organic crystal is orders of magnitudes lower than the one for bulk crystals, making (scanning) transmission electron microscopy characterization very challenging. In this work we present an atomically resolved study on the dynamics of a monolayer CuPcCl\textsubscript{16} crystal under the electron beam as well as an image of the undamaged molecules obtained by low-dose electron microscopy. The results show the dynamics and the radiation damage mechanisms in the 2D layer of this material, complementing what has been found for bulk crystals in earlier studies. Furthermore, being able to image the undamaged molecular crystal allows the characterization of new composites consisting of 2D materials and organic molecules.